Typewriter platen



Patented Oct.- l6, 1934 'UNITED STATES PATIazrJT clerics John H. Sperry, Jamaica Plain, Mass. Application November 1, 1933, Serial No. 696,188

s claims. (ci. 19t-144) This invention relates to a lrotary platen such as is employed in typewriters tov support the paper and receive-the impact or blow of the t in the` printing operation.-

The object of the invention is to provide a construction which enable an impression to be produced of the same character that would be produced by a substantiallylesser impact or blow of the type if the machine were operating with the usual platen and without'the present invention embodied therein.

While the invention is useful for various purposes, it is particularly designed to enable an ordinary typewriter to produce impressions of the same character as that produced in duplicating machines such as multigraph work, thus enabling the typewriter to ll in addresses and other matter in such work in such. a `manner that the filled-in portions shall be of the same character as the body of the work and'practically indistinguishable therefrom.

` The nature and objects of the invention will appear more 'fulb" from -the accompanying description and drawing and will be particularly pointed out in the claims. Y Y

As the invention relates entirely to the rotary typewriter platen, it Vis only necessary toiillus- Y trate and describe a preferred construction thereof. v

In the drawing:

Fig. 1 is a view partially in longitudinal cross section of a rotary typewriter platen embodying the invention.

. Fig. 2 is a view the une 2 2 of Fig. 1. .The platen of this invention comprises essen-i tially a rigid core, a hollow cylindrical rubber sheath, and a thin, resilient cylindrical shell.

in transverse sectiontaken lon Y AThe rigid core maybe made of any suitable Ypma-- 40 terial and is shown as chiey formed .of-wood. It presents at the ends the cylindrical heads l and 2. These heads may be reinforced with metal portions carrying suitable gudgeons or connections `by which the platen` is rotarily 5 mounted and operated in the typewriting machine. For this purposethe- ,head 1 includes the metal disk 3V having the gudgeon 4, while the head2 includes the metal disk 5V having the elements' of suitable form for' mounting and effecting the `rotation ofthe pieten. Between the heads 1 and 2 -the intermediate section 7 of the core is of a length not lless than the width ofthe printing area 'or the-area over which the type 'operate in producing the printing impressions. 'I 'he diameter of this intermediate Se@ tion is substantially less than thediameter ofV the heads. For a typewriter platen ofl ordinary size thediameter of this intermediate section should be about one-eighth of an'A inch less than the diameter vof the heads but it'may be of any 30 lesser amount so long as the intermediate section is left of the required strength and rigidity.

The hollow'cylindrical sheath is formed of'y rubber 8 preferably with a backing or lining of 65 fabric 9 'and is preferably of the usual construction employed in typewriter platens to support the paper and receive the impact or blow of thetype. A

Between the sheath 8 and the rigid core is 70 mounted a thin, resilient cylindrical shell.y .This may be of any material suitable for the purpose. Itextends at least throughout the interior4 of the sheath over the intermediate section of the core and nts snugly and closely against the interior of the sheath. Preferably this thin re- A silient sheet extends the full length of the sheath" and fits closely over the core heads. A thin "sheet of celluloid of about .010 to .015- inches in thickness has been found particularlyeadvantageous in securing the desired results.- This thin resilient cylindrical shell is shown at 10 and closely tsr' the interior of the sheath throughout, while at its ends it ts closely over the core heads 1 and 2. It will benoted that the 8,5

sheet of celluloid is not brought into overlapping 1 relation at its edges but presents a circumferentially and longitudinally continuous ,exteriorcylindrical surface at the interior of the sheath throughout the printing area at least, and, as f illustrated, preferably throughout the full length Y of the sheath. The term ,continuous is employed herein, and in the claims, not to dif"v ferentiate between a shell formed from a sheet -brought into cylindrical form with its edges abuttingand a shell formed as an integral-tubo of 4uniform thickness, nor to dierentiate between a shell having va solid wall and ashell-f whose wallV is skeletonized, but todeflne the uniformity or regularity of. the supporting action mo l; y

ofthe shell throughout the printing area both circumferentially and longitudinally for the pur-"1 pose of the invention.

The sneu eers normally to support the rubber sheath and maintain its cylindricalform bei tween the core heads, but at the same time 'it allows the sheath to yield under the impact or blow of the typesuiliciently to produce an impression of the samecharacter that would be produced by a substantially .lesser impact or'flvlo described tted over a solid core in 2 l blow of the type upon a .sheath similar to that usual in typewriters.

The invention, as pointed out, is particularly useful in connection with any type of duplicating machine work of which the multigraph work is a leading example.' The normal force exerted by the type in a multigraph machine in producing the impression onl the paper is very much less'than the torce exerted by the type' of a typewriter in producing the impression upon the paper. For example, the force exerted by the type of a' multigraph is about three ounces, while that exerted by' the `type of .the typewriter is about seven ounces. But with the present invention the same quality and character of ribbon which is employed in the .multigraphwork can be used in a typewriter 1. A r'tary typewriter platen. comprising a idcore having cylindrical heads at each end lwith the intermediate lsection oi.' a length not less than the width of the printing area and oi' a diameter substantially less than .that of the,

heads, a hollow-cylindrical rubber sheath surrounding the core to4 receive the impa'ct or .'blow 4oi the type and a thin resilient shell ot the manner lwith the intermediate section o! a lengthl not less than the width of the printing area and of a'diameter -substantially less than that of the uniform thickness presenting a cylindrical surface circumierentiaily and longitudinally co'ntinuous throughout the lwidthvv of the printing area and closely iltting the interior of the sheath and acting normally to supoprt the rubber sheatha'nd maintain its cylindrical form be'' tween the core heads while allowing'itf to yield under the impact or blow of the typer suiiiciently to produce an impression 'of the character produced by a substantially lesser impact or b low oi the type upon a similar sheath'iltted over a solid core. s i

2. A rotary typewriter platen comprising a rigid.. core having cylindrical heads at each end heads, a hollow cylindrical rubber sheath surrounding the core te receive the impact or blow of the type and a. thin'resilient shell of uniform thickness presenting a cylindrical surface circumferentially and longitudinally contin` nous throughout the width of the printing area. and closelyv tting the interior of the sheath and at its ends closely fitting over the core heads and acting normally to support the rubber. sheath and maintain its cylindrical form between the core heads while allowing it to yield under the impact or blow of the type sufficiently to pro- A duce an impression oi' the character produced by 1:15

a substantially lesser impact or blowof the type upon a similiar sheath tted over a solid core.

3. A rotary typewriter platen comprising the construction and acting as defined in claim 2, in which the thin resilient cylindrical shell is a, sheet of celluloid.

JOHNHVSPERRY. 

